From 9cbdfb3a2f501a4eaa68981d836005d6d8257295 Mon Sep 17 00:00:00 2001 From: Richard van der Hoff Date: Thu, 23 Apr 2020 15:45:12 +0100 Subject: [PATCH] Make it clear that the limit for an update_function is a target --- synapse/replication/tcp/streams/_base.py | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-) diff --git a/synapse/replication/tcp/streams/_base.py b/synapse/replication/tcp/streams/_base.py index 112bfead5..4ae3cffb1 100644 --- a/synapse/replication/tcp/streams/_base.py +++ b/synapse/replication/tcp/streams/_base.py @@ -24,8 +24,8 @@ from synapse.replication.http.streams import ReplicationGetStreamUpdates logger = logging.getLogger(__name__) - -MAX_EVENTS_BEHIND = 500000 +# the number of rows to request from an update_function. +_STREAM_UPDATE_TARGET_ROW_COUNT = 100 # Some type aliases to make things a bit easier. @@ -56,7 +56,11 @@ StreamUpdateResult = Tuple[List[Tuple[Token, StreamRow]], Token, bool] # * from_token: the previous stream token: the starting point for fetching the # updates # * to_token: the new stream token: the point to get updates up to -# * limit: the maximum number of rows to return +# * target_row_count: a target for the number of rows to be returned. +# +# The update_function is expected to return up to _approximately_ target_row_count rows. +# If there are more updates available, it should set `limited` in the result, and +# it will be called again to get the next batch. # UpdateFunction = Callable[[Token, Token, int], Awaitable[StreamUpdateResult]] @@ -138,7 +142,7 @@ class Stream(object): return updates, current_token, limited async def get_updates_since( - self, from_token: Token, upto_token: Token, limit: int = 100 + self, from_token: Token, upto_token: Token ) -> StreamUpdateResult: """Like get_updates except allows specifying from when we should stream updates @@ -156,7 +160,7 @@ class Stream(object): return [], upto_token, False updates, upto_token, limited = await self.update_function( - from_token, upto_token, limit, + from_token, upto_token, _STREAM_UPDATE_TARGET_ROW_COUNT, ) return updates, upto_token, limited